When trying to start a Flashpoint, my party members are seeing a message that says my difficulty is on a different setting than theirs.

 

• This only happens on Flashpoints I've completed before (it was >24hrs since my last run).
  
• When I start the dialog as the party leader, the other members don't see the green radius and are unable to join the conversation. They receive a message that I am "on a different difficulty".
  
• If someone else starts the conversation, I cannot join it.
  
• I am unable to enter the instance after my party members go in.
  

 

I am lvl 23 and was attempting to run with people who had never done the Flashpoint before.

 

Any thoughts on why this is happening and how to fix it?

I don't know, but can i ask how you set a flashpoint to a harder difficulty? I didn't think that was possible till you hit 50?

Your guess is as good as mine. I don't think it's possible to change difficulty before lvl 50.

 

I've completed the Flashpoint once before with no problems or noticeable issues.

I dont understand it either, but it didnt seem to make a difference.

This post seems to describe the same situation. It also provides some possible workarounds:

http://www.swtor.com/community/showthread.php?t=45652

I have seen this message before, but in my experience it goes away and everyone is able to zone in once the party leader enters the flashpoint. Edited December 19, 2011 by IncognitoCat

Had this last night. It was because my buddy had picked up a "report to this and that person" from a flashpoint courier, and i hadn't.

He shared the mission with me, and everything worked as it should after that.

This is because not everyone has the quest from the terminal. or the leader does not either.